Final answer:
A country that can produce items more efficiently has a comparative advantage while being the most efficient producer means it holds an absolute advantage. Specialization based on comparative advantage enables countries to gain from trade, increasing global production and consumption.
Step-by-step explanation:
When a country specializes in products that it can supply more efficiently or at a lower cost than it can produce other items, the country has a comparative advantage; if the country is the most efficient producer of a unique item, it has an absolute advantage. A country with an absolute advantage requires fewer resources to produce a good compared to other countries, often due to natural endowments or more productive processes. On the other hand, a comparative advantage arises when a country can produce a good at a lower cost in terms of other goods. By specializing in goods where they have a comparative advantage, countries gain from trade as they can consume more than they could produce alone. This specialization and subsequent trade lead to an increase in global production levels and higher levels of consumption for all participating countries.